Leakage indicator system



J l 6 T. REISSMANN ETAL 2 2 57 LEAKAGE INDICATOR SYSTEM Filed Oct. 3, 1951 INVENTOR /Rifl 54a: F a/m4: ,4- 95/55 BY f ATTORN Patented July 6, 1954 UNITED STATE i TENT OFFICE LEAKAGE INDICATOR SYSTEM Application October 3, 1951, Serial No. 249,618

4 Claims.

This invention relates to a leakage indicator system and more particularly relates to such a system which is capable of indicating leakage into a suture tube of a fluid which has a deleteriouseffect on a catgut suture or ligature. U. S. Patent No. 2,470,494, describes a hermetically sealed shipping package of suture'tubes in which sealed glass tubes containing tubing fluid, usually consisting of an aqueous alcohol solution, are immersed in a sterilizing liquid which is usually an aqueous alcohol solution containing a minor amount of an antiseptic material such as formaldehyde. Such a shipping package of suture tubes has received wide acceptance by the medical pro fession because suture tubes, sterile on the outside, are readily available and the troublesome and time-consuming procedure formerly required to render sterile the outside of the tubes before they were opened in the operating room or surgeons office is obviated.

A sterilizing liquid in contact with the outside of the suture tube is customarily about 70 per cent aqueous isopropyl alcohol and contains, as a specific sterilizing agent, about one per cent of formaldehyde. The tubing fluid inside the sealed glass tube containing non-boilable catgut sutures or ligatures is ordinarily an approximately 90 per cent aqueous alcohol solution. Sutures remain pliable and stable and retain their strength in such a solution. The open end of glass tubes containing a suture or ligature wound on a reel, a paper label and tubing fluid is sealed by a gas flame and after the sealed end of the tube cools, a slight negative pressure is present in the tube so that if any crack is present after sealing or develops later due to strains in the glass, liquid outside the tube may be drawn through the crack into the tube in small amounts. Even traces of formaldehyde have a decided and deleterious efiect on the stability and strength of the catgut. Accordingly'it has been found of considerable importance to be able to detect the presence in suture tubes of even minute amounts of a sterilizing liquid which contains formaldehyde and unless the crack in the tube is large enough for ready detection upon quick examination in the operating room, the medical practitioner may use a defective suture or ligature at a critical point in an operation.

Heretofore, one means of facilitating the detection of defective sutures due to traces of sterilizing liquid being present in a suture tube, has been to add a .dye to the sterilizing liquid, but this has not proved satisfactory because in some instances, the amount of sterilizing liquid entering a crack in a defective tube has been so small as to preclude detection by this means.

It is an object of this invention to supply the medical profession with a ship-ping package of suture tubes in which the presence in the suture tube of even a minute amount of sterilizing liquid may be instantaneously detected.

It is another object of this invention to supply the medical profession with a shipping package of suture tubes in which the suture tube contains a colorless internal indicator, stable in the presence of the contents of the tube and in which the sterilizing liquid contains an external indicator, soluble, and stable in the said liquid; the internal indicator being capable of turning to a bright and readily detectable color in the presence of traces of the external indicator.

Still other objects of the invention will be apparent from the following descriptive material and the appended claims.

In the following description reference will be made to the accompanying drawing forming a part hereof and in which: 7

Figure 1 represents a side elevation of an assembled hermetically sealed container containing suture tubes and sterilizing solution with part .of the container broken away, and part of a suture tub-e broken away, and also showing an hermetically sealed suture tube containing a suture wound on a reel and tubing fluid;

Figure 2 represents a top plan view of an assembled hermetically sealed container containing suture tubes and sterilizing fluid with part of the container broken away;

Figure 3 represents a side elevation of an hermetically sealed suture tube with part of the suture tube broken away, and showing a suture wound on a reel; and

Figure 4 represents a horizontal section of the suture tube taken along the line 44 of Figure 3.

It has now been discovered that a composition comprising a plastic substance and a minor amount of a nickel salt may be used as an internal indicator and that a minor amount of dimethylglyoxime may be used as an external indicator. If even traces of the sterilizing liquid containing the external indicator get into the suture tube, through defects such as pin holes or cracks resulting from defective sealing of the suture tube, the internal indicator composition will turn pink to bright red in color depending upon the amount of sterilizing liquid present in the suture tube and defective sutures may thus be readily deteoted and rejected.

Referring to the drawing, Figures 1 and 2 show an assembled container unit H) in which a plurality of sealed glass suture tubes 16 containing surgical sutures I! wound on a notched strip l8, and a sterile tubing fluid are immersed in a sterilizing solution 22 contained in a container body [2 which is hermetically sealed to the container lid M. The preferred type of container is one fabricated of metal and preferably with a friction closure, and it is also preferred that the assembled unit H) be hermetically sealed and fabricated in such a way as to be conveniently opened.

Figures 3 and 4 show a single hermetically sealed glass tube containing a reel l8 having wound thereon a suture H, a tubing fluid 20 and a plastic or paper label 3| having thereon a thin layer of an internal indicator composition 32 composed of a plastic and a nickel salt.

The composition comprising the internal indicator is preferably composed of a plastic which is insoluble or soluble only to the extent of traces in a tubing fluid such as approximately 90 per cent aqueous isopropyl alcohol. Satisfactory plastics include gelatin, polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, and polyvinyl butyral. The internal indicator composition contains a nickel salt which is insoluble or soluble only to the extent of less than one gram per liter in approximately 90 per cent aqueous isopropyl alcohol. The composition preferably contains approximatel one per cent of the nickel salt but may contain the said nickel salt in an amount from within the range of from 0.1 to per cent. It has been discovered if more than 10 per cent of the nickel salt is present in the internal indicator composition, there is insufiicient adhesiveness of the composition to a plastic or paper label in the suture tube and if less than 0.1 per cent of the nickel salt is present in the internal indicator composition, the change in color of the composition produced by the presence of the external indicator in the tubing fluid is not sufficiently readily detectable. Nickel salts such as nickel sulfate, nickel nitrate, nickel ammonium sulfate and organic salts of nickel in general have been found particularly suitable for use in the internal indicator composition. All nickel salts soluble in approximately 90 per cent aqueous isopropyl alcohol to the extent of less than one gram per liter are suitable for use in this invention.

The sterilizing liquid surrounding the sealed suture tubes generally contains approximately '70 per cent aqueous isopropyl alcohol and about one per cent of formaldehyde. Dimethylglyoxime is the external indicator used in the practice of this invention and is preferably present in the sterilizing liquid in an amount within the range of from 0.5 to one per cent although the indicator may be present in an amount greater than one per cent but if the amount of the external indicator is less than 0.5 per cent it has been found that there is not suflicient color contrast produced in the internal indicator composition when minute amounts of the sterilizing liquid containing the external indicator are present in the tubing fluid.

Although the invention has been discussed above with reference to a specific tubing fluid, approximately 90 per cent aqueous isopropyl alcohol, it is to be understood that the inven tion is operable even if ethyl or other low molecular weight alcohols are substituted for isopropyl alcohol provided a plastic in the internal indicator composition is chosen which is substantially insoluble in the tubing fluid and further provided that a nickel salt used in the internal indicator composition is selected which is soluble in the tubing fluid to the extent of less than one gram per liter.

A specific composition of the sterilizing liquid has been referred to above but it is to be understood that the composition of the sterilizing liquid is not a controlling factor in the invention provided at least 0.5 per cent of dimethylglyoxime is soluble in the sterilizing liquid. It has been discovered that the reaction between the dimethylglyoxime in the sterilizing liquid and the nickel salt in the internal indicator composition in the tubing fluid whereby a pink to red color is produced will take place in the presence of alcohol even under anhydrous conditions.

It is the customary practice to have present in the suture tube a paper label on which are printed size, length and other pertinent information concerning the catgut in the tube as well as a paper or plastic reel on which the catgut strand is wound. The reel may also function as and replace the label. In the preferred embodiment of the invention, the internal indicator composition is coated on the label or reel in the suture tube and this is preferred because the presence in the tubing fluid of free particles of the nickel salt is undesirable, for the said particles may contaminate the catgut and be introduced as undesirable foreign bodies into body tissues during suturing or ligating. This method of using the internal indicator is also preferred because any change in color is readily detected when the said internal indicator composition is coated on a white label or reel.

In one example illustrating the practice of the invention, an internal indicator composition comprising a mixture of gelatin containin one per cent of nickel ammonium sulfate was thinly coated on a paper label in a suture tube containing, as a tubing fluid, per cent, aqueous isopropyl alcohol and the tube was sealed. A plurality of such tubes was placed in a can containing a sterilizing liquid comprising a 70 per cent aqueous solution of isopropyl alcohol containing one per cent formaldehyde and one per cent dimethylglyoxime. The amount of sterilizing liquid in the can was sufficient to completely cover the suture tubes. The can was hermetically sealed. It was found that the presence of even minute amounts of the sterilizing liquid in the tubing fluid of defective tubes of this example was readily detectable because the internal indicator composition was bright red in color in defective tubes.

All percentages in the above example and description of the invention are by weight.

Various changes in details of method, composition, and amounts other than those described could be made without departing from the broader principles of the invention embodied therein and defined in the appended claims.

What is claimed is:

1. In a package of a plurality of suture tubes and sterilizing liquid in a container in which the suture tubes contain surgical sutures wound on a reel and an aqueous alcohol solution as a tubing fluid, and in which the sterilizing liquid is an aqueous alcohol solution; the improvement which comprises the presence in the tubing fluid of an internal indicator composition coated on a solid strip, comprising a nickel salt, soluble to the extent of less than one gram per liter in the tubing fluid, mixed with a plastic, adhesive to said solid strip and having only slight solubility in the tubing fluid; and the presence in the 5 sterilizing liquid, as an external indicator, of at least 0.5 per cent by weight of dimethylglyoxime.

2. A package according to claim 1 in which the internal indicator composition is present as a thin film on a paper strip present in the sealed suture tube.

3. A package accordin to claim 1 in which the internal indicator composition is present as a thin film on a suture reel present in the sealed suture tube.

4. In a package of a plurality of suture tubes and a sterilizin liquid in a container in which the suture tubes contain an approximately 90 per cent aqueous isopropylalcohol solution as a tubing fluid and a surgical suture wound on a reel, and in which the sterilizing liquid is an approximately 70 per cent aqueous isopropylalcohol solution containing approximately one per cent formaldehyde; the improvement which comprises the presence in the suture tube of a composition coated on a solid strip, comprising a nickel salt, soluble to the extent of less than one gram per liter in the tubing fluid, mixed with a plastic, adhesive to the solid strip and having only slight solubility in the tubing fluid; and the presence in the sterilizing liquid of at least 0.5 per cent by weight of dimethylglyoxime.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,843,234 Karnes et a1. Feb. 2, 1932 2,228,737 Tandberg et a1 Jan. 14, 1941 2,452,036 Clardy Oct. 26, 1948 2,470,494 Kennison May 17, 1949 

